Android : How set value spinner when change textEdit of preferenceScreen?

when Change value of TextEdit of preference Screen, I want that textEdit of ManinActivity change...How can I do?.

    @Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
        String key) {
    if (key.equals(PrefUserName)) {

        SharedPreferences sharedPref = PreferenceManager
                .getDefaultSharedPreferences(getApplication());

        String textoEditTextPreference = sharedPref.getString(key,
                "");
        // Spinner spinner = (Spinner) findViewById(R.layout.activity_main);


        //Here I want add value spinner of main activity...

// Spinner spinner = (Spinner) findViewById(R.layout.activity_main);

        Toast.makeText(
                getApplication(),
                "New name of user: "
                        + textoEditTextPreference, Toast.LENGTH_SHORT)
                .show();
    }

Thanks!!!